Reviewing the Pro Football Hall of Fame's list of middle linebackers is a sobering experience.

The position is well-represented, but almost all of the enshrinees -- Dick Butkus, Jack Lambert and Willie Lanier among them -- are drawn from a long-gone era of NFL defenses. In fact, former Chicago Bears star Mike Singletary is the only current Hall of Fame middle linebacker whose career started in the past 36 years.

The best case to be made for Brian Urlacher's candidacy, now that he has announced his retirement, is that his career reversed the decades-long decline in the value of the position. Along with the Baltimore Ravens' Ray Lewis, Urlacher modernized middle linebacking by adding speed and regular playmaking to the traditional role of helmet-jarring hits and fierce leadership.

Hall of Fame players can't simply be top performers over a period of NFL seasons. In a competitive environment where ballots are limited to five enshrinees per year, candidates must stand out. Some might be the best players in a generation, but if their position is as undervalued as middle linebacker has been over the past few decades, they also would need to have changed or impacted the game in a unique way.

I think Urlacher did that. It helped that he was drafted by a team that soon moved to a scheme that perfectly fit a middle linebacker who could run like a safety. It also helped that in his best years, Urlacher had some stud defensive tackles in front of him who limited free shots from offensive linemen.

Regardless, the Bears' defense in the Lovie Smith era wouldn't have worked without Urlacher covering the deep third of the field while also holding his own at the line of scrimmage. His ability to get 25 yards downfield, in between chasing runners from sideline to sideline, was a new development for the modern-day middle linebacker.

When Urlacher was sidelined, for 15 games in 2009 and four games last season, the Bears' defense dipped noticeably and obviously, especially against the pass. In the games that Urlacher missed over that stretch, opponents' Total Quarterback Rating (QBR) rose from 39.5 to 60.1 (on a scale of 0-100), according to ESPN Stats & Information.

He is one of four players in NFL history with at least 40 sacks and 20 interceptions in his career, as the chart shows, and he is one of seven players to win the NFL's Defensive Rookie of the Year and Defensive Player of the Year award. Of the other six, three are in the Hall of Fame and two others aren't yet eligible.

Urlacher's résumé of sustained elite performances, even after his 2009 wrist injury, and his notable impact on how the game is played merit Hall of Fame enshrinement. How long it will take for him to be elected is almost a silly discussion. We don't know what the backlog will be like in 2018, but there is a pretty strong group of players who will be eligible for the first time alongside Urlacher. The group includes Lewis, Steve Hutchinson, Ronde Barber and perhaps Randy Moss.

Timing, of course, is but a detail. I'm sure there will be plenty of discussion between now and then. But you would think Canton has room for Brian Urlacher. Frankly, he made that space for himself.